Constipation and Megacolon

Question 1

What are the short duration colonic contractions?

Answer 1

stationary motor contractions, prseent over short areas of colon, causes mixing of fecal material and extraction of water, persists for less than 15 seconds

Question 2

What are long duration colonic contractions?

Answer 2

may be stationary or propagate for short distances, may travel in orad or aboral direction
assists in mixing and local propulsion of feces
migrates towards rectum in distal colon

Question 3

What are the giant migrating complexes of the colon?

Answer 3

propagates aborally over extended distances, causes mass mvmt, normally occuring 1-2 times.day, may be precipitated by colonic distention

Question 4

What mediates the gastrocolic reflex?

Answer 4

cck, in response to food intake,

Question 5

What is the role of CCK in colonic motility?

Answer 5

causes increased frequency and amplitude of segmental contractions

Question 6

WHat is the role of Pg F in colonic motility

Answer 6

stimulated longitudinal muscle contraction

Question 7

What is the role of PgE in colonic motility

Answer 7

inhibits circular muscle contraction

Question 8

What is the role of serotonin in colonic motility

Answer 8

mediates intestinal peristalsis and secretion in GI tract as well as modulation of pain perception

Question 9

What releases serotonin?

Answer 9

enterochromaffin cells

Question 10

What is the epidemiology of constipation?

Answer 10

12-19%

more common in little physical acitivty, low income and poor education, over 65 years of age and women

Question 11

What is the usual cause of pediatric constipation?

Answer 11

constipation (functional)

Question 12

What lab tests should you order when evaluating constipation?

Answer 12

CBC, glucose, creatinine, calcium, TSH

Question 13

what are sitzmarks?

Answer 13

they are a capsule of 24 radioopaque markers. if over 80% of markers are passed by day 5, the colon transit normal. also can tell you where there is a problem.

Question 14

what is pelvic floor dyssynergia?

Answer 14

ineffective defecation associated with a failure to relax, or inappropriate contraction of, the puborectalis and eas muscles.

Question 15

What is lubiprostone?

Answer 15

a chloride channel activator

Question 16

what is hirschsprung dz?

Answer 16

congential disorder characterized by obstipation from birth and colonic dilatation proximal to a spastic, non-relaxing and nonpropulsive segment of distal bowel.

Question 17

What is the epidemiology of hirschsprung dz

Answer 17

males, 10% of down syndrome cases, most cases sporadic

Question 18

What is the pathogenesis of hirschsprung dz?

Answer 18

absence of ganglion cells in large bowel, function obstruction and proximal dilatation

Question 19

What parts of involved in hirschsprung dz? not involved?

Answer 19

always involved is rectum, rectum and sigmoid in most cases.

Question 20

what is the clinical presentation of hirschsprung dz?

Answer 20

failure to pass meconium
obstructive constipation, occasional passage of stool
bouts of diarrhea and abdominal distention

Question 21

what is the ddx for acquired megacolon?

Answer 21

c. difficile
IBs (uc or chrons dz)
obstructino
function disorder ie psychiatric
chagas dz: trypanosomes destroying enteric plexus

Question 22

What drugs are associated with megacolon

Answer 22

psychiatric drugs

Question 23

what do yousee on rectal biopsy of hirschsprung dz?

Answer 23

nerve without ganglion cells (definitive dx)

Question 24

70 wf htn high cholesterol smoking hypothyroid, br ca, diabetes, osteoporsis, lumbar fracture, MI rectal bleeding 7 yrs ago with diverticulitis. ER with constipation, used prunes, suppositories. cause if meds? cause if not meds?

Answer 24

if meds, opiates

if not meds, hypothyroidism or immobility

Question 25

same case, do to dx cause:

Answer 25

sitz or anorectal manometry

Question 26

how to tx until dx:

Answer 26

polyethylene glycol